Wonderments of Cosmos Seminar 1: Professor Ofer Lahav
By Lucy M J Calder, on 6 March 2014
The seminar series began in style last Tuesday (February 25) with a brilliant talk by Ofer Lahav ( UCL Physics and Astronomy) describing, among much else, the standard scientific model of Cosmology and its development.
Download the audio for Seminar 1 HERE,
Ofer discussed the discovery of the Cosmic Microwave Background (CMB), the evidence for Dark Matter, and the supernovae observations in 1998, which are evidence for the accelerating expansion of the universe, pausing here to mention the recent UCL discovery of a supernova in galaxy M82. He explained how Dark Energy, which has been invoked to explain the universe’s acceleration, is almost exactly equivalent to the cosmological constant (lambda), a term that Einstein added to his general relativity field equations in 1917 to give a static solution, then definitively rejected when Hubble’s evidence showed that the universe is expanding.
The Dark Energy Survey is currently trying to find out a lot more about Dark Energy, and Ofer described some of the methods they are using, and UCL’s contribution to the international collaboration. Another possibility is to reject the idea of Dark Energy altogether and instead modify Einstein’s gravitational theory, and this choice – modify a theory or add a new entity – is quite a common dilemma in the history of physics. Ofer pointed out the possible benefits of scientists working on problems in isolation, as happened during the Cold War, because it can lead to different ways of approaching a problem, or different answers altogether. This point was taken up by Jon Butterworth in his Guardian blog (JB was also at the Seminar) to argue that when isolated scientists come to the same conclusions via different routes (such as the development of quantum electrodynamics), it gives scientists confidence in their theories ( implying, I suspect, that the theories truthfully represent reality).
You can download Professor Lahav’s slides HERE.
Dilwyn Knox (UCL European Languages, Culture and Society) then bravely refuted everything Ofer (Olaf!) had told us, describing the alternative picture of cosmology in the Renaissance and pointing out that there is no longer any room in modern Cosmology for the individual human being. In the Renaissance picture the microcosm that is the human is intimately connected to the macrocosm outside, through the medium of the human mind. A fundamental change came about when Giordano Bruno developed the Copernican model into an infinite universe, because infinity is impossible for the human mind to cope with. Dilwyn pointed out that the idea of the Wonderment of the Cosmos is ancient, and people have perhaps always been awed by the universe. Quoting Genesis, he told us that the light created out of darkness on the first day was not visual light as we thing of it, but ‘intelligible’ light/matter – ‘energy that has not yet been put into motion’ – this could be thought of as equivalent to the Big Bang. In effect, both Renaissance cosmologists and modern physicists are using metaphors as ways to grapple with these mind-bending notions. The old question, of course, is whether our descriptions and mathematical models really correspond to underlying truths. (I leave it to the reader to interpret the terms ‘truth’ and ‘reality’!)
The second respondent, David Napier (UCL Anthropology), acknowledging the challenge posed by an inter-disciplinary discussion on this topic, put forward two possible Anthropological approaches to cosmology:
The first is to think about looking at the sky through a telescope – it’s an empirical process but you are actually looking into the past, without the use of a time machine, and when you think about it this is profound. Consider our ideas about aliens – we imagine them more like people from other cultures (like us but with alien value systems) than as completely alien beings. In fact, the real study of alien ideas falls to anthropologists, who study different ways of thinking around the world – or to novelists and writers (e.g Borges, or Edwin Abbott’s ‘Flatland’ [this is a great book, often recommended to undergraduate physics students to start them thinking about reference frames]). Trying to imagine alternative worlds is hard work ‘even at times intriguing and repulsive’ – attaching new ideas to familiar concepts is challenging because we expect to be able to take them for granted.
His second point is that if we want other modes to reshape our thinking about what is possible, ‘they’re out there if we take the time and effort to learn about them’. He gives the example of Balinese cosmology. The more you know, however, the more you realise what you cannot know. The more you think you know the spatial extent of the universe, the more it alerts you to what is ‘dark’. Real wisdom consists in holding the knowing and not knowing in creative tension. There is value in accepting what we do not know and acknowledging cosmic mystery. How can we understand the infinite not-known based on the finite known? Bertrand Russell gave an example of the increasing feelings of secruity of a well fed chicken in the days leading up to Thanksgiving. It feels safest just before the slaughter. Scientists tells us mostly about what we already know, as do economists.. History gets moved by what we do not know, not by what we know. ‘ The true events that create the future are also those that most revise the past. For that reason dark energy and dark matter do in fact matter, more than we could ever imagine.’
Obviously I’m paraphrasing, and not conveying the humour or the humanity, but you can download the whole seminar HERE, including the thought provoking conversation which followed the speakers.
For example, the first question Prof. Lahav was faced with was ‘what is the difference between astrology and astronomy?’ which isn’t something he has to cope with in the Astrophysics Group. He explained more about the Planck space telescope’s image of the CMB and there was a discussion about the use of examples, models, metaphors; the simplicity of ideas; beauty; time; multiverses; approximations; paradigm shifts; and the inestimable value in independent ways of thinking about the world.
Cosmology concerns us all, as Ian Scott (UCL Grand Challenges) reminded us at the end, and we all have the right to think about and comment on these questions.
The sense of excitement in the room was certainly an indication that these are ideas we should be discussing across the disciplines.
Images (from top): Dark Energy Survey, Dark Energy Camera, DES, DECAM, Cerro Tololo Observatory, Chile. Credoit: Reidar Hahn, Fermilab.
Copernicus Model. Credit: Copernicus, De Revolutionibus Orbium Coelestium
Planck CMB. Credit: ESA and the Planck Collaboration